Stop flickering!


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Dave
Dave
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We set up an experiment where most of the screen contents remain constant across the whole experiment, while only a few stimuli are rotated, sized, moved or replaced during trials. Needless to say, regarding the topic of this thread, we cannot have flicker between stimulus alterations. Subjects have to respond to certain changes and are also entitled to trigger specific events. Due to the dynamic nature of the changes we need to enforce a "one trial, one transformation" strategy to allow for realtime subject responses and immediate reactions to these responses. The transformations themselves require a lot of erasing, depending on size and shape of the stimuli. It would have been very helpful if the erase-feature was available but blank occluders will do the trick, too.


In such cases, it usually helps to use the '/ erase' settings and your "occluders" smartly / efficiently. As an example, consider the two attached scripts.


~Dave


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HappyTrails.zip (332 views, 3.00 KB)
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NIfty scripting!



The "erase" setting is entirely out of the picture in our case since a stimulus will be replaced with another stimulus in any instance, rather than with a blank area. Setting "erase" to true will yield flicker in such cases, hence we must rely on blank shapes.


Bye, Malte.


Dave
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Well, then the only practical help I can offer is to assist you in optimizing your script's setup, i.e. finding ways to keep the number of required occluders / blank shapes as low as possible. Let me know and I'll be here to help.


Cheers,


~Dave


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Thanks Dave,


the script is already done. I've decided to go with a set of small blank shapes and calculate their positions to occlude an arbitrarily sized area. Works well.


Bye, Malte.


GO

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